Drug delivery from internally implanted biomedical devices used in traumatology and in orthopedic surgery

Millions of people receive annually an internal device aimed to repair or reconstruct damaged bone, and different therapeutic moieties are administered during or after surgery generally using systemic routes. The local administration of those moieties using in situ drug-eluting devices emerges as an alternative to minimize undesired side effects in healthy tissues, optimize the amount of drug needed, and reduce the costs.

In vitro and in vivo published evidence regarding the performance of internally implantable drug-loaded biomedical devices for traumatology and orthopedic surgery are reviewed in this article, the problems that are encountered, and the main challenges in the development of a new generation of devices.

An insight of past and current efforts to control the rate of drug release from devices, as well as the requirements that future developments may fulfill, such as responding 'on demand' after biological signaling or communicating the device with the exterior.

The main drawback for proper design of devices having improved capabilities mainly remains in the lack of understanding with regards to the complex regulation of physiopathological mechanisms and the thermodynamics at the interface between the implant surface and the surrounding tissue. The potential toxicity and risk versus benefits of any new drug-eluting device need to be evaluated carefully.